If you're willing to spend as much on Marvin windows I'd see if you can get ahold of the new VistaLuxe line by Kolbe. Contemporary look on the inside and out, has better thermal numbers than all aluminum products. If you need to keep tighter on budget you could go with Integrity All Ultrex, their casement looks nice and they have dark exterior colors and the interior fiberglass can be painted to any color you want on site.

How tight and energy efficient a home do you want to build?

By the way...keep us posted on the build.

Maine is gorgeous and I can't wait to see what you come up with.

I ended up going with Kolbe Ultra EP in black exteriors. We too were debating between painted black interiors as well, but decided to go with natural interiors so we can decide on colors later. Glad I did since we left the natural with drywall returns. We have strand bamboo floors, so I used wood from that to build sills for the windows. The touch of natural wood helps keep natural elements inside the house. However we did go with black painted trims (base and casing on doors). Love the combos.
Anyway, love the black exterior. I have also installed a lot of windows, and they installed very easily. The largest window was a factory mulled 8'x7' 8 (see in the image below) triple pane window. It took 5 guys and a fork lift to set it, but it did not flex one bit installing it.
The Ultra EP is a triple pane window. I worked closely with Kolbe on the design to make sure the windows were tuned for solar gain on the south and low u on the north. My house too is a highly efficient home (I went with ICF basement and main. It tested at as an Energy Star 5+ star, leakage rate of 1.03 @ 50 pac and a HERs score of 37).
The windows work great. I am in north east Iowa, and this first winter has been a test of the ages for the home and window performance. Its very common for the furnace to never run on a sunny day at 0 outside. Gas bills for the 3900 sqft home have been running around $70 this winter. The glass keeps the main floor space roughly 70-72 during a sunny day no matter the exterior temp. Point is, thinking about window and roof design in the plan is very important.
Put as much money into the shell as you can. This doesnt always mean expensive windows. Rather look at values of the windows, leakage rates, etc. To be 100% honest, Kolbe was not my first pick however, and the only reason is I wanted a fiberglass window with a lot of glass options vs aluminum wood clad. My first pick was a black fiberglass triple pane from Inline windows from Canada. Only reason I did not go with them is the delivery schedule fitting into my construction schedule.
However I am happy, so far, with the Kolbe. They have been installed for about a year now.

Here is a picture of the home under construction 8 months ago.

Looks like she is going to be a stunner.

If you want more information on the windows and more pictures, you can check out my blog. The link below takes you to the window section, but feel free to check out other sections if you want. A lot of info in there about energy efficiency, air sealing, different wall types, sun diagrams, etc. Also pictures of the construction process and finished home.

Here is a link that might be useful: home building link

I work in the window industries for a window distributor. I would suggest looking at E-Series (Eagle) by Andersen which is an aluminum clad exterior wood interior. they have more options than almost anyone. If I was building a house I would choose E-Series over any other product

Here is a link that might be useful: Eagle website